<!DOCTYPE html>
<html lang='en'>
<head>
    <meta charset='UTF-8'>
    <meta name='viewport' content='width=device-width, initial-scale=1.0'>
    <title>Document</title>
    <script type='text/javascript' src='js/vue.js'></script>
</head>
<body>
    <div id='app'>
        {{msg}}====

        <form action="">
            <input type="text" v-model.number='a'>+
            <input type="text" name="" id="" v-model.number='b'>
            <input type="button" value="=" >
            <span>{{sub}}====我是computed:={{total}}</span>
        </form>
    </div>
    <script type='text/javascript'>
        var vm = new Vue({
            el: '#app',
            data: {
                msg: 'Hello Vue',
                a:1,
                b:2,
                sub:3
            },
            methods:{},
            directives:{},
            filters:{},
            computed:{
                total(){
                    console.log(111111);
                    return this.a+11
                }
            }
        });
    </script>
</body>
</html>